Insect Metamorphisis

“All those things I was taught in school that I didn’t need to know.”


In the next few paragraphs, we will be talking about insects, most importantly aquatic insects. First things first, what’s an insect? In the grand scheme of living things man breaks down everything into categories. Kingdom, Phylum, Class, Order, Family, Genus, Species; is any of this sounding familier yet?

In the animal kingdom under the Phylum Arthropoda there is a Class called Insecta.
In order to be in this Class you must have:

  • 3 body parts (head, thorax, & abdomen)
  • 3 pairs of jointed legs
  • 1 or 2 pairs of wings
  • 1 pair of antennae
  • and absolutely no legs on your abdomen

Ok, now we know what an insect is. From here on out it will start to get interesting.

Identifying insects gets complicated because they change. Not just a little change but great big ones. Aquatic insects go from being water breathing bottom crawlers to air breathing flies. Kind of like a butterfly but the catapillar lives under water. This is called Metamorphosis, which means change. In aquatic insects there are two kinds of Metamorphosis, complete metamorphosis and incomplete metamorphosis.

Complete Metamorphosis


Insects that have complete metamorphosis go through four different stages. Those stages are egg, larva, pupa, and adult. The aquatic insects that go through complete metamorphosis are (listed common name first, then order):

  • Caddisflies – Trichopter
  • Midges – Diptera
  • Dobsonflies – Megaloptera
  • Alderflies – Megaloptera
  • Aquatic Moths – Lepidoptera
  • Aquatic Beetles – Coleoptera

Incomplete Metamorphosis


Insects that have incomplete metamorphosis go through three different stages. Those stages are egg, nymph, and adult. The aquatic insects that go through incomplete metamorphosis are (listed common name first, then order):

  • Stoneflies – Plecoptera
  • Mayflies – Ephemeroptera
  • Dragonflies – Odonata
  • Damselflies – Odonata

Now that we have covered insects and metamorphosis we can move on with a detailed descriptions of each stage of metamorphosis in life stages of insects.